This invention relates to an apparatus and a method for generating digital images or photographs.
The digital images or photographs generated with a conventional digital camera are normally not safe from subsequent tampering, i.e. it cannot be guaranteed that a digital image has not been subsequently tampered with. In many cases, however, it is required that unambiguous proof can be furnished that a digital image has not been subsequently tampered with, i.e. that its integrity has not been corrupted. Besides the integrity of a digital image, a further important aspect is its authenticity with regard to the photographer as the author, since authenticity with regard to the photographer enables the identity of the author of the digital image, i.e. of the photographer, to be unambiguously established, and this person thus to be identified as the owner of the copyright of a digital image.
Both integrity and authenticity with regard to the photographer as the author of a digital image can be important in particular in the following cases. Digital photographs taken in the course of police investigations or court proceedings can quite generally only be employed as evidence when it is certain that no subsequent changes have been made in the digital photographs. Further, the photographer must normally identify himself accordingly. In structural surveys relating to building measures, digital photographs can be employed for example to document structural damage or prove that work has been performed correctly. In such cases, too, it can be required that both the integrity and the authenticity of the digital photographs can be ascertained or guaranteed. The same holds for the documentation of medical operations by means of digital images or photographs.
The prior art discloses digital cameras which, upon the recording of a digital image, already furnish it with a digital signature and optionally encrypt it in the camera. For this purpose, such a digital camera has corresponding cryptographic keys deposited therein. A background system has accordingly matching cryptographic keys deposited therein, in order to enable a digital image to be decrypted again and the digital signature to be tested.
The publication “Securing Embedded Smart Cameras with Trusted Computing”, Thomas Winkler and Bernhard Rinner, EURASIP Journal on Wireless Communications and Networking, Volume 2011, Article ID 530354, describes a video surveillance system having a multiplicity of surveillance cameras, wherein the integrity of video data recorded with the video surveillance system, and their authenticity with regard to a surveillance camera employed therefor, are guaranteed by the surveillance cameras of the video surveillance system being respectively equipped with a security chip or security module in the form of a Trusted Platform Module (TPM).